This application relates to the production of oxazolidines having the formula ##STR2## in which R is C.sub.1 -C.sub.10 haloalkyl, C.sub.1 -C.sub.10 alkyl or lower alkylthio; R.sub.1 and R.sub.2 are independently hydrogen, C.sub.1 -C.sub.12 alkyl, lower alkoxyalkyl or lower alkylol; and R.sub.3, R.sub.4, R.sub.5 and R.sub.6 are independently hydrogen, lower alkyl, lower alkoxyalkyl or lower alkylol.
In describing the above group of compounds, the terms "alkyl" and "haloalkyl" include members which contain from 1 to 10 or 12, carbon atoms inclusive, as indicated, in both straight and branched chain configurations, the term "halo" including chloro and bromo with substitution being either of the mono, di, tri, tetra and/or per from. For instance, the alkyl portion may be a group such as methyl, ethyl, n-propyl, isopropyl, n-butyl, sec.-butyl,1,1-dimethylbutyl, amyl, isoamyl, 2,4,4-trimethylpentyl, n-hexyl, isohexyl, n-heptyl, n-octyl, isooctyl, nonyl, decyl, dimethylheptyl, and the like.
The terms "lower alkyl", "lower alkylthio", "lower alkoxyalkyl" and "lower alkylol" preferably include such groups which contain from 1 to 6, most preferably from 1 to 4 carbon atoms, inclusive, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec.-butyl, tert.-butyl, pentyl, hexyl and the like; methylthio, ethylthio, n-propylthio, isopropylthio, n-butylthio, and the like; methoxymethyl, ethyoxyethyl, hydroxymethyl, hydroxy-n-propyl, and the like.
Compounds of this type have been found to possess activity as herbicidal antidotes and, in some cases, as herbicides, and are disclosed in several publications including, for instance, Belgian Pat. Nos. 782,120, 806,038 and 806,040 and German Offenlegungsschrift No. 2,341,810. Representative examples of compounds of this type are included in Table I, hereinbelow.
TABLE I __________________________________________________________________________ ##STR3## Compound Number R R.sub.1 R.sub.2 R.sub.3 R.sub.4 R.sub.5 R.sub.6 __________________________________________________________________________ 1 CHCl.sub.2 H H H H H H 2 CHCl.sub.2 CH.sub.3 CH.sub.3 H H H H 3 CHCl.sub.2 CH.sub.3 CH.sub.3 H H CH.sub.3 H 4 CHCl.sub.2 CH.sub.3 CH.sub.3 H H n-C.sub.3 H.sub.7 H 5 CH.sub.2 Cl CH.sub.3 CH.sub.3 H H H H 6 CBr.sub.3 CH.sub.3 CH.sub.3 H H H H 7 CH.sub.2 Br CH.sub.3 CH.sub.3 CH.sub.3 CH.sub.3 H H 8 CHCl.sub.2 CH.sub.3 CH.sub.3 C.sub.2 H.sub.5 H H H 9 CCl.sub.3 CH.sub.3 H H H CH.sub.3 H 10 CCl.sub.3 C.sub.2 H.sub.5 H C.sub.2 H.sub.5 H H H 11 CHCl.sub.2 CH.sub.3 CH.sub.3 CH.sub.3 CH.sub.3 H H 12 CHCl.sub.2 CH.sub.3 t-C.sub.4 H.sub.9 H H H H 13 CHCl.sub.2 H H CH.sub.3 CH.sub.3 H H 14 CBr.sub.3 H H C.sub.2 H.sub.5 H H H 15 CHCl.sub.2 CH.sub.3 i-C.sub.3 H.sub.7 H H H H 16 CBr.sub.3 CH.sub.3 C.sub.2 H.sub.5 H H H H 17 CBr.sub.3 C.sub.2 H.sub.5 H H H H H 18 CH.sub.3 CHBr CH.sub.3 CH.sub.3 H H CH.sub.3 H 19 CH.sub.3 CHBr C.sub.2 H.sub.5 H H H CH.sub.3 H 20 CH.sub.2 Br CH.sub.3 CH.sub.3 C.sub.2 H.sub.5 H H H 21 CH.sub.2 Br CH.sub.3 H H H H H 22 CH.sub.3 (CHBr).sub.4 CH.sub.3 CH.sub.3 H H H H 23 ClCH.sub.2 CH.sub.2 CH.sub.3 CH.sub.3 H H H H 24 CH.sub.2 BrCHBr CH.sub.3 t-C.sub.4 H.sub.9 H H H H 25 CHBr.sub.2 C.sub.2 H.sub.5 H H H H H 26 (CH.sub.3).sub.2 CBr C.sub.2 H.sub.5 H H H CH.sub.3 H 27 CCl.sub.3 CH.sub.3 H H H H H 28 CH.sub.2 BrC(CH.sub.3)Br CH.sub.3 H H H CH.sub.3 H 29 CH.sub.2 BrCH.sub.2 CH.sub.3 CH.sub.3 H H H H 30 Cl(CH.sub.2).sub.3 CH.sub.3 CH.sub.3 H H H H 31 CH.sub.3 CHClCH.sub.2 CH.sub.3 CH.sub.3 H H H H 32 C.sub.2 H.sub.5 CHBr CH.sub.3 CH.sub.3 H H CH.sub.3 H 33 C.sub.3 H.sub.7 CHBr CH.sub.3 CH.sub.3 H H H H 34 CH.sub.2 ClCH.sub.2 CH.sub.2 CH.sub.3 CH.sub.3 H H CH.sub.3 H 35 CH.sub.2 Br(CH.sub.2).sub.4 CH.sub.3 CH.sub.3 H H CH.sub.3 H 36 C.sub.2 H.sub.5 S H H C.sub.2 H.sub.5 H H H 37 C.sub.2 H.sub.5 S CH.sub.3 H H H CH.sub.3 H 38 C.sub.3 H.sub.7 S CH.sub.3 CH.sub.3 C.sub.2 H.sub.5 H H H 39 i-C.sub.3 H.sub.7 S CH.sub.3 CH.sub.3 C.sub.2 H.sub.5 H H H 40 CH.sub.3 S CH.sub.3 H C.sub.2 H.sub.5 H H H 41 n-C.sub.4 H.sub.9 S CH.sub.3 H C.sub.2 H.sub.5 H H H 42 C.sub.6 H.sub.13 CH.sub.3 CH.sub.3 H H H H 43 CHCl.sub.2 C.sub.3 H.sub.7 H H H H H 44 CHCl.sub.2 CH.sub.3 OCH.sub.2 H H H H H 45 CH.sub.2 Cl CH.sub.3 CH.sub.3 H H n-C.sub.3 H.sub.7 H 46 CHCl.sub.2 CH.sub.3 CH.sub.3 CH.sub.3 CH.sub.2 OH H H 47 CH.sub.2 Cl n-C.sub.5 H.sub.11 H CH.sub.3 CH.sub.3 H H 48 CH.sub.2 Cl 2.6-dimethylheptyl H CH.sub.3 CH.sub.3 H H 49 CH.sub.2 Cl n-C.sub.3 H.sub.7 CH.sub.3 CH.sub.3 CH.sub.3 H H 50 CH.sub.2 Cl C.sub.2 H.sub.5 C.sub.2 H.sub.5 CH.sub.3 CH.sub.3 H H 51 CH.sub.2 Cl n-C.sub.3 H.sub.7 n-C.sub.3 H.sub.7 CH.sub.3 CH.sub.3 H H __________________________________________________________________________
In one preferred embodiment, R.sub.1 and R.sub.2 are independently hydrogen, lower alkyl, lower alkoxyalkyl or lower alkylol.
Additional compounds of this type are disclosed in the copending U.S. Pat. application No. 566,019 of Eugene G. Teach, filed Apr. 7, 1975, now U.S. Pat. No. 3,959,304.
According to the prior art, oxazolidines were generally prepared by the condensation of alkanolamines with a suitable aldehyde or ketone in a solvent such as benzene, with water being removed from the reaction product. Such a method is described, for instance, in the article by Bergmann et al., JACS 75 358 (1953). In order to produce N-substituted oxazolidines of the formula shown above, the product of this reaction was further treated with an acid chloride in the presence of a hydrogen chloride acceptor, such as triethylamine. This reaction was conducted in the anhydrous state, the water having been removed after the condensation of the alkanolamine with the carbonyl compound. Processes of this type, for example, are described in the above-mentioned Belgian patents.
Substituted oxazolidines produced in this manner are frequently contaminated with by-products, generally resulting from the reaction of the acid chloride with by-products or reaction intermediates formed during the condensation step. These by-products have often proved difficult to separate either because of their quantity or their chemical behavior, or both. In the production of substituted oxazolidines on a small scale, such as for laboratory or testing purposes, the desired product can be obtained in the substantially pure state with sufficient purification. Such purification steps, however, may result in sufficient product loss as to be detrimental if the desired product is to be produced on a larger scale, for instance, commercially. Furthermore, the elimination or reduction of such purification steps would be advantageous in a commercial facility since the installed and/or operating cost could be reduced by the cost of equipment and/or solvent not required.
It is an object of the present invention to provide an improved process for the production of oxazolidines.
A further object of the present invention is to provide an improved process for the production of N-substituted oxazolidines.
Another object of the present invention is to provide a process for the production of N-substituted oxazolidines of adequate purity.
Yet a further object of the present invention is to provide a process for the production of N-substituted oxazolidines requiring fewer purification steps than previously.
Still another object of the present invention is to provide a process for the production of N-substituted oxazolidines in which the production of undesirable by-products can be minimized.